Petraria Arcatinus

What is a Petraria Arcatinus? Roughly translated, it means "Bow powered rock hurler". There has been much debate over whether these machines actually existed or not. There is very little in the historical record to suggest a machine like this, but there are a lot of artists drawings from ancient times depicting bow powered, spoon armed machines.

We built a lot of machines based on those drawings, and they usually didn't work worth beans. But, taking what we learned and committing to creating a bow-powered catapult that really works, we eventually discovered this design.

This elegant little machine is highly versatile. Capable of hurling just about anything ranging in size and weight from marbles to baseballs. We were able to hurl golf balls about 50 feet, and baseballs sailed nearly 20 feet! Powered by a bow with a 50 pound pull, this little machine is only 18 inches long and 10 inches wide. The arm reaches 18 inches high at rest.

Because the world needs good engineers and scientists, and because the kids who will grow up to become engineers and scientists need a way to get hands-on experience with physics, math and engineering.

In this age of 200-plus channels of TV, the Internet and computer games, kids are also spending far less time building tree houses, tinkering with engines, or designing downhill racers. We believe those are important skills to have. They help form the basis for good problem solving skills and an innate understanding of the real, physical world that you just can't get from a computer game, no matter how good its physics simulation software is.

Ballistic motion was one of the key players in the development of the science of physics. The word "engineer" even originated as the builders and designer of Siege Engines

Why is a budding engineering student expected to take a year or two of calculus in high school, but she isn't
expected to have any real-world experience in building or working with machines and materials? Pencil and paper
(or computer screens) are only one part of the learning experience. Where will she apply all of the stuff she
learned in geometry and trig? Without physical projects to touch, feel and see, the lessons become abstract,
their utility questionable.

A catapult project gives students a chance to see that science and engineering really can be fun, and it's a lot
more than just numbers on paper. The real payoff for an engineer is in the field, where she can see and enjoy the
results of her ingenuity. And it may seem counterintuitive, but engineering projects not only help kids learn math
and science, they are also great at getting kids back outdoors, away from the massive over-exposure to video games,
TV and the Internet.

Why all this interest in getting kids to study science and engineering? Because it's important to our society,
and it's great mental cross training regardless of what field of work the kids eventually go into. Most people
develop a sense for what they want to do in life while they are still in high school or even earlier.
A catapult project is fun and interesting enough to inspire some kids to study the science behind how they
work, and then go on to become the engineers and scientists of tomorrow.